Bleaching powder



Patented Sept. 30; 1924.

UNITED STATES CHARLES A. GAMMAL, OF WORCESTER, MASSACHUSETTS.

BLEACHING POWDER.

Ho Drawing.

T 0 all whom it my camera:

Be it known that 1, CHARLES A. GAMMZAL, a citizen of the United States, residing at Worcester, in the county of Worcester and State of Massachusetts, have invented a new and useful Bleachin Powder, of whichthe following is a speci cation.

This invention relates to certain improvements in the manufacture thereof b which the bleaching efiiciency of the pow or may be much increased. Ordinary commercial bleaching powder is known to be very unstable and rapidly deteriorates when stored for any length of time.

It is the general object of my invention to provide a method of preparing bleaching powder by which the'constituents thereof,

may be stabilized and by which the amount and efliciency of the active bleaching agent may be substantially increased.

In the following specification, I have de scribed the details of operation of my improved method or process, together with certainmodifications thereof, and the essential features of my invention are more specifically set forth in the appended claims. Commercial bleaching powder is a combination of lime, calcium chloride and calcium hypochlorite, which substances apparentl form some kind of a loosely associate chemical compound. This compound, however, is very unstable and loses a large part of its avaliable chlorine if stored or exposed to dampness or to increased temperature for any. considerable period.

I have discovered that the treatment of such commercial bleachingmpowder by adding water thereto and t ereafter drying out or otherwise removing the water has a very important effect in stabilizing the elements of the bleaching powder and in increasing the proportion of hypochlorite, which is the princi al bleaching agent. The product thus obtained may be exposed for days to a temperature of 100 degrees centigrade, without substantial loss of available chlorine, whereas commercial bleaching powder would be almost entirely decomposed within a few hours if exposed to the same tem rature.

Inone' orm of my invention, the water is added to the bleaching powder in sufiicient quantities to form a thick paste or cream,

themanufacture of ableaching powder and particularly to:

Application filed February 19, 1924. Serial No. 893,888.

after which the product is carefully dried out at controlled temperatures, starting at a relatively low heat and gradually increasing the temperature.

Commercial bleaching powder ordinarily contains from 35% to 40% chloride, from 30% to 35% hypochlorite, and from 15% to 20% lime, the balance being made up by moisture and impurities. By treating the bleaching powder as above described, the proportion of hypochlorite may be increased to above 45% and the proportion of chloride will be reduced to below 30%, with .an accompanying increase inthe prcportiou of lime. As the hypochlorito is the activ bleaching agent, the efliciency .of the bleaching powder is thereby substantially increased and the product has the further very important advanta e of increased stability.

A second metho of treating the bleaching powder is to add water as in the first method, but to remove the greater part of the water b mechanical means, such as filtration an pressure, after which the remaining cake or product is dried to remove the balance of the water. This treatment appears to be even more efiicient than the first described method and the proportion'of hypochlorite may be increased to from to or over with a substantial reduc tion in the percentage of chloride.

A third method of stabilizing commercial bleaching powder consists in treating the powder successively with water and ethyl alcohol or with a mixture of water and alcohol. alcohol alone will not remove calcium chloride from bleaching powder but that calcium chloride by itself is soluble in ethyl alcohol. By treating the bleaching'powder with water before or at the same time that it is treated with alcohol, the bleaching powder appears to be broken up and the calcium chloride is so separated that it may be'dissolved by the alcohol.

It is also possibleto treat the bleaching powder as described under the first or second forms of my improved process and to thereafter treat the result-ant product with alcohol to reduce the proportion of calcium chloride. This latter process may be advisable when a very high test product extremely rich in available chlorine is desired.

This third form of m improved rocess may also be carried out y the use 0 other It is well established that ethyl D will be seen that in all forms of m solvents for calcium cloride as well as by ethyl alcohol.

Having thus described my invention, it

improved process the treatment of the b eaching powder by the addition of water which is thereafter substantially removed forms a very important step in the process. This simple treatment is of very great commercial importance as it may be carried out at low cost and the increased stability of the product is of the greatest advantage.

Having thus described my invention and the advantages thereof, I do not wish to be limited to the details herein disclosed, otherwise than as set forth in the claims, but what I claim is 1. The process of stabilizing bleaching powder which consists in treating commercial bleaching powder with water, and thereafter removing the water.

2. The process of stabilizing bleaching powder which consists in treating commercial bleaching powder with water and thereafter drying out the water.

3. The process of stabilizing bleaching powder which consists in treating commercial bleaching powder with water and thereafter drying out the water at gradually in creasing; temperatures, thereby substantially increasing the available chlorine and stabilizing the powder.

4. The process of stabilizing bleaching powder which consists in treating commercial bleaching powder with water, remov-' ing the greater part of the water by me chanical means, and thereafter drying out substantially all. of the remaining water whereby the stability of the compound and the proportion of available chlorine are both substantially increased.

5, The process of stabilizing bleaching powder which consists in treating commercial bleaching powder with water, filtering and pressing the wet bleaching powder to remove the surplus water therefrom, and thereafter drying out the remaining water, whereby the powder is stabilized and the proportion of calcium chloride is substantially reduced.

6. The method of stabilizing bleaching powder which consists in treating commercial bleaching powder with water and with ethyl alcohol, removing the surplus liquid, and thereafter drying out the residue, whereby the powder is stabilized and a considerable portion of the calcium chloride is removed.

7. The method of stabilizing bleaching powder which consists in treating commercial bleaching powder with water and with an additional and different solvent for calcium chloride, removing the surplus liquid, and thereafter drying out the residue, whereby the powder is stabilized and a considerabl portion of the calcium chloride is removed.

8. The method of stabilizing bleaching powder which consists in treating commercial bleaching powder with water, removing the water therefrom, treating the resultant substantially dry product with an additionaland different solvent for calcium chloride, and again drying out the residue.

In testimony whereof I have hereunto afiixed my signature.

CHARLES A. GAMMAL. 

